Screening of high quality acitic acid bacteria from grains of Sichuan bran vinegar and its characteristics of producting acid

Five high-yielding acetic acid bacteria(C9-4,C12-4,A30-16,A12-7 and A30-14-2) were screened from Sichuan bran vinegar grains,they were all identified as Acetobacter pasteurianus by analysis of morphological,physiological and biochemical characteristics,and 16 S r DNA genetic identification. The results of acid-producing characteristics of the 5 high-yielding strains showed that C9-4,A30-14-2 and A30-16 could adapted to 9%(v/v) ethanol,all of the 5 strains could stand 4% acid concentration. The results of ethanol addition tests showed that strain C9-4 could transform ethanol to acid continuously most. C9-4,A30-16 and A30-14-2 could still produce acid at 40℃. Acid producing rates of strains C9-4,A30-16 and A30-14-2 were higher than that of strains C12-4 and A12-7 under the same condition. The total amount of organic acids produced by the 5 strains were as follows:A30-16>C12-4>C9-4>A30-14-2>A12-7.